this may not be step by step but sort of how i do this. i have two systems i use, one is my main macbookpro and th eother is a macbook that is used around the house and shared with others, so of course the ability to throw my 200GB+ library on there isnt a good option.

i have an external drive with all my iTunes music + converted iTunes/AppleTV/iPod videos on there and in iTunes I went to:

iTunes > Preferences (COMMAND Comma) then selected Advanced and changed the location of my library on each machine.

Then i proceeded to drag the "Music" folder into iTunes and let it compile the library list.

took awhile but then when it was done everything was matched up.

as fara s when it updates, the only way ive been able to sync it was to goto File > Add To Library and it should sync anything you havent added, otherwise i just drag and drop the new stuff in anyways.

there may be less "archaic" way to do it but it has worked for me, and when im at home i usually toss the drive on the network so i can remotely access it at both systems.

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